Hydrogenation and ethynylation catalysts

ABSTRACT

A process for preparing a catalyst includes impregnating a metal oxide carrier with an aqueous solution to form an impregnated carrier; drying the impregnated carrier to form a dried, impregnated carrier; and heat-treating the dried, impregnated carrier in air to form the catalyst; wherein: the aqueous solution includes a copper salt; and from about 3 wt % to about 15 wt % of a C3-C6 multifunctional carboxylic acid; and the catalyst includes from about 5 wt % to about 50 wt % copper oxide.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/557,578, filed on Sep. 12, 2017, now U.S. Pat. No. 10,399,062, whichis a U.S. National Phase Application under 35 U.S.C. § 371 ofInternational Application No. PCT/US2016/024912, filed on Mar. 30, 2016,which claims priority to U.S. Provisional Application Nos. 62/140,877,filed Mar. 31, 2015, and 62/242,010, filed Oct. 15, 2015, the entirecontents of which are incorporated herein by reference in theirentireties.

FIELD

The present technology is generally related to catalysts. Morespecifically, the technology is related to hydrogenation,dehydrogenation, ethynylation, and hydrogenolysis catalysts.

SUMMARY

In one aspect, a process is provided for the ethynylation offormaldehyde to make 1,4 butynediol. The process uses a catalystprepared by impregnating a metal oxide carrier with a copper saltsolution, and optionally a bismuth salt, containing from 3 wt % up to 15wt % of at least one multifunctional carboxylic acid having from about 3to 6 carbon atoms to form an impregnated carrier, drying the impregnatedcarrier, and calcining the impregnated carrier, where the catalystcontains from about 5 wt % to about 40 wt % copper oxide.

In another aspect, a process is provided for forming a catalyst forhydrogenation, dehydrogenation, or hydrogenolysis, the process includingimpregnating a metal oxide carrier with an aqueous solution to form animpregnated carrier; drying the impregnated carrier to form a dried,impregnated carrier; and heat-treating the dried, impregnated carrier inair to form the catalyst. The aqueous solution of the method includes acopper salt; and from about 1 wt % to about 15 wt % of a C₃-C₆multifunctional carboxylic acid; and the catalyst includes from about 5wt % to about 40 wt % copper oxide. In some embodiments, theimpregnating is carried out until incipient wetness is achieved. Wherethe catalyst is a hydrogenation catalyst, in some embodiments, theaqueous solution consists essentially of the copper salt, from about 1wt % to about 15 wt % of a C₃-C₆ multifunctional carboxylic acid, and,optionally, a precipitation agent.

In some embodiments, the heat-treating includes calcining in air. Inother embodiments, the heat-treating includes pyrolyzing. In otherembodiments, the heat-treating includes calcining in an oxygen-limitedatmosphere.

In another aspect, an ethynylation catalyst prepared according to any ofthe methods described herein is provided.

In another aspect, a process is provided for the synthesis ofbutynediol. The process may include contacting formaldehyde andacetylene under ethynylation conditions with any of the ethynylationcatalysts described or prepared herein. The process may includeactivating the ethynylation catalyst by forming Cu(I)acetylide.

In another aspect, a hydrogenation catalyst prepared according to any ofthe methods described herein is provided.

In another aspect, a process is provided for the hydrogenation ofaldehydes and ketones to alcohols, dehydrogenating alcohols to aldehydesand ketones, or hydrogenolysis of esters to alcohols under reducingconditions with any of the catalysts described or prepared herein. Inone aspect, a process is provided for the hydrogenation of butyraldeydeto butanol under hydrogenation conditions with any of the catalystsdescribed or prepared herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a high magnification image of Example-1A “0 wt % Citric Acid”catalyst using Scanning Electron Microscopy, according to the examples.

FIG. 2 is a lower magnification image of Example-1A “0 wt % Citric Acid”catalyst using Scanning Electron Microscopy, according to the examples.

FIG. 3 is a high magnification image of Example-1B “5 wt % Citric Acid”catalyst using Scanning Electron Microscopy, according to the examples.

FIG. 4 is a lower magnification image of Example-1B “5 wt % Citric Acid”catalyst using Scanning Electron Microscopy, according to the examples.

FIG. 5 is a high magnification image of Example-1C “10 wt % Citric Acid”catalyst using Scanning Electron Microscopy, according to the examples.

FIG. 6 is a lower magnification image of Example-1C “10 wt % CitricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 7 is a high magnification image of Example-2A “0 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 8 is a lower magnification image of Example-2A “0 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 9 is a high magnification image of Example-2B “1 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 10 is a lower magnification image of Example-2B “1 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 11 is a high magnification image of Example-2C “5 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 12 is a lower magnification image of Example-2B “5 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 13 is a high magnification image of Example-2D “7 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 14 is a lower magnification image of Example-2D “7 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 15 is a high magnification image of Example-2E “10 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 16 is a lower magnification image of Example-2E “10 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 17 is a high magnification image of Example-3A “0 wt % MalonicAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 18 is a lower magnification image of Example-3A “0 wt % MalonicAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 19 is a high magnification image of Example-3B “2.5 wt % MalonicAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 20 is a lower magnification image of Example-3B “2.5 wt % MalonicAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 21 is a high magnification image of Example-3C “4.2 wt % MalonicAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 22 is a lower magnification image of Example-3C “4.2 wt % MalonicAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 23 is a high magnification image of Example-3D “5.8 wt % MalonicAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 24 is a lower magnification image of Example-3D “5.8 wt % MalonicAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 25 is a high magnification image of Example-3E “7.5 wt % MalonicAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 26 is a lower magnification image of Example-3E “7.5 wt % MalonicAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 27 is a high magnification image of Example-4A “0 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 28 is a lower magnification image of Example-4A “0 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 29 is a high magnification image of Example-4B “3 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 30 is a lower magnification image of Example-4B “3 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 31 is a high magnification image of Example-4C “5 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 32 is a high magnification image of Example-4D “7 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 33 is a high magnification image of Example-5A “1.5 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 34 is a lower magnification image of Example-5A “1.5 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 35 is a high magnification image of Example-5B “2.5 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 36 is a lower magnification image of Example-5B “2.5 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 37 is a high magnification image of Example-5C “3.5 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 38 is a lower magnification image of Example-5C “3.5 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 39 is a high magnification image of Example-5D “5.0 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 40 is a lower magnification image of Example-5D “5.0 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 41 is a high magnification image of Example-5E “7.0 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 42 is a lower magnification image of Example-5E “7.0 wt % GlutaricAcid” catalyst using Scanning Electron Microscopy, according to theexamples.

FIG. 43 is a graph illustrating the improved activity of the catalystfrom Samples 1A-C, observed in the ethynylation reaction.

FIG. 44 is a graph illustrating the improved activity of the catalystfrom Samples 2A-E, observed in the ethynylation reaction.

FIG. 45 is a graph illustrating the improved activity of the catalystfrom Samples 3A-E, observed in the ethynylation reaction.

FIG. 46 is a graph illustrating the improvement to Cu dispersion inExample 3.

FIG. 47 is a graph illustrating the improved activity of the catalystfrom Samples 4A-D, observed in the ethynylation reaction.

FIG. 48 is a graph illustrating the improvement to Cu dispersion inExample 4.

FIG. 49 is a graph illustrating the improved activity of the catalystfrom Samples 5A-E, observed in the ethynylation reaction.

FIG. 50 is a graph illustrating the improved activity of the catalystsof Examples 6A-E.

FIG. 51 is a graph illustrating the improvement to Cu dispersion forSamples 6A, 6C and 6E.

DETAILED DESCRIPTION

Various embodiments are described hereinafter. It should be noted thatthe specific embodiments are not intended as an exhaustive descriptionor as a limitation to the broader aspects discussed herein. One aspectdescribed in conjunction with a particular embodiment is not necessarilylimited to that embodiment and can be practiced with any otherembodiment(s).

As used herein, “about” will be understood by persons of ordinary skillin the art and will vary to some extent depending upon the context inwhich it is used. If there are uses of the term which are not clear topersons of ordinary skill in the art, given the context in which it isused, “about” will mean up to plus or minus 10% of the particular term.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the elements (especially in the context of thefollowing claims) are to be construed to cover both the singular and theplural, unless otherwise indicated herein or clearly contradicted bycontext. Recitation of ranges of values herein are merely intended toserve as a shorthand method of referring individually to each separatevalue falling within the range, unless otherwise indicated herein, andeach separate value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein, isintended merely to better illuminate the embodiments and does not pose alimitation on the scope of the claims unless otherwise stated. Nolanguage in the specification should be construed as indicating anynon-claimed element as essential.

In one aspect, a process is provided for the preparation ofhydrogenation, dehydrogenation, ethynylation, or hydrogenolysiscatalysts. The catalysts may be used in a variety of processes,including the hydrogenation aldehydes, ketones and esters alcohols. Insome embodiments, the process provides for the preparation ofhydrogenation catalysts. For example, in one embodiment the conversionof butyraldehyde to butanol, or the ethynylation of formaldehyde to 1,4butynediol (i.e. the “Reppe Process”).

The process uses a catalyst prepared by impregnating a metal oxidecarrier with an aqueous copper salt solution, and optionally a bismuthsalt, containing from about 1 to about 15 wt % of at least onemultifunctional carboxylic acid having from about 3 to 6 carbon atoms toform an impregnated carrier, drying the impregnated carrier to form adried impregnated carrier, and heat-treating the dried impregnatedcarrier to form the catalyst, where the catalyst contains from about 5wt % to about 50 wt % copper oxide. In some embodiments, from about 3 toabout 15 wt % of at least one multifunctional carboxylic acid areemployed, and the catalyst contains from about 5 wt % to about 40 wt %copper oxide. The heat-treating may include calcination or pyrolysis asdescribed vide infra.

In forming the catalyst, a metal oxide carrier is impregnated with anaqueous copper salt solution, and the solution may optionally alsocontain a bismuth salt. The metal oxide carrier is typically aparticulate material having an average particle diameter from about 5 μmto about 100 μm. In some embodiments, the particulate material has anaverage particle diameter from about 10 μm to 40 μm.

The aqueous copper salt solution also contains at least onemultifunctional carboxylic acid having from about 3 to 6 carbon atoms.In some embodiments, the aqueous copper salt solution may contain fromabout 1 wt % to about 15 wt % of the multifunctional carboxylic acid. Insome embodiments, the aqueous copper salt solution may contain fromabout 3 wt % to about 15 wt % of the multifunctional carboxylic acid.The metal:carboxylic acid ratio on a molar basis may be from about 1 toabout 15, or from about 5 to about 9. Illustrative copper salts include,but are not limited to, copper sulfate, copper nitrate, copper acetate,copper chloride, and copper citrate. In some embodiments, the coppersalt is Cu(NO₃)₂. Illustrative bismuth salts include, but are notlimited to, bismuth nitrate, bismuth chloride, bismuth citrate, bismuthsulfate, and bismuth acetate. In some embodiments, the bismuth salt isBi(NO₃)₃.

Illustrative multifunctional carboxylic acids include, but are notlimited to, malonic acid, glutaric acid, citric acid, or a combinationof any two or more thereof. Where the multifunctional carboxylic acidincludes malonic acid, in some embodiments, the copper:malonic acidration may be from about 2:1 to about 3.5:1. Where the multifunctionalcarboxylic acid includes glutaric acid, in some embodiments, thecopper:glutaric acid ration is from about 5:1 to about 9:1.

In preparing the catalyst, the aqueous copper salt solution is appliedto the metal oxide carrier until an incipient wetness impregnation(“IWI”; filling 90% of pore volume of the metal oxide carrier, asmeasured by N₂ adsorption), is reached. The temperature at which theimpregnation phase of the catalyst preparation is conducted is heldconstant throughout the impregnation process. The temperature may befrom about 20° C. to about 90° C.

After impregnation of the metal oxide carrier with the aqueous coppersalt solution, the thus impregnated carrier is dried at a temperaturefrom about 100° C. to about 125° C., until substantially all of the freewater in the impregnated carrier is removed, and a dried, impregnatedcarrier is formed. In some embodiments, the temperature for drying isabout 110° C.

The dried impregnated carrier is then heat-treated in air to form thecatalyst. The heat-treating temperature may vary from about 250° C. toabout 750° C. In some embodiments, the heat-treating temperature is fromabout 300° C. to about 400° C. The heat-treating may be conducted for aslong as necessary. This may be from, in some embodiments, from about 5minutes to about 5 hours.

The catalyst may contain from about 5 wt % to about 50 wt % cupric oxide(CuO). This may include from about 5 wt % to about 40 wt %, or fromabout 15 wt % to about 35 wt %, in other embodiments. As noted, bismuthmay optionally be present in the aqueous copper salt solution, andaccordingly bismuth may optionally be present in the catalyst. Wherebismuth is present, it may be present as bismuth oxide in the catalystup to about 5 wt %. This may include from about 0.5 wt % to about 5 wt%, or from about 2 wt % to about 4 wt %, in various embodiments.

The copper dispersion on said catalyst is at least about 0.5% asmeasured by the selective N₂O dissociation method as described videinfra. In another embodiment, the copper dispersion includes from about0.5% to about 15%.

As described above, the carrier may be a metal oxide. The metal oxidemay variously be, a siliceous material, alumina, titania, zirconia, or acombination of any two or more thereof. The siliceous material mayinclude silica or metal silicates, such as Group II and III metalsilicates, including, but not limited to, clays which include aluminumsilicates. The metal oxide carrier may also be comprised ofgamma-alumina. In some embodiments, the carrier material is silica(SiO₂). The metal oxide carrier may have a pore volume from about 0.3ml/g to about 2.5 ml/g. Where the metal oxide carrier is silica, thesilica may also have a pore volume in some embodiments, from about 1ml/g to about 1.8 ml/g. Where the metal oxide carrier is alumina, thealumina may also have a pore volume in some embodiments, from about 0.5ml/g up to about 1.5 ml/g. Impurities in the metal oxide carrier may bepresent in small amounts. Other silicate materials with differentcompositions may be used. Silica-only carriers, without other metals,may also be used effectively.

Ethynylation processes generally vary from practitioner to practitioner.It is believed that the catalysts described above with reference totheir preparation will be applicable to all specific types ofethynylation processes. For example, an ethynylation process using thecatalyst of this invention can be that as described in U.S. Pat. No.3,920,759.

It will be appreciated that the ethynylation catalysts described hereinwill require activation prior to use in any chemical synthesisprocesses, including ethynylation. As described in U.S. Pat. No.3,920,759, a catalyst is activated by means of the introduction ofacetylene into a formaldehyde-catalyst reaction medium. When activatingthe catalyst, the catalyst in situ is subjected to the simultaneousaction of the reactants at the required pressure in a substantiallyaqueous medium at a temperature of about 60° C. to about 120° C. Attemperatures substantially outside this range, or in strongly basic oracidic media, or acetylene partial pressures greater than 2 atmospheres,or in the substantial absence of either formaldehyde or acetylene, poorcatalyst formation is generally observed. In some embodiments, thecatalyst generation temperature is from about 60° C. to about 120° C.The pH of the aqueous medium is typically in the range of about 3 toabout 10. In some embodiments, the pH of the aqueous medium is fromabout 5 to about 6, and preferably 5 to 6. The concentration offormaldehyde in the aqueous medium is ordinarily in the range of about 5wt % to about 60 wt %. This may include from at least 10 wt % to about60 wt %, or from about 30 wt % to about 40 wt %, in various embodiments.

The partial pressure of acetylene over the aqueous medium is from about0.1 atmospheres (atm) to about 1.9 atm. In some embodiments, the partialpressure of acetylene over the aqueous medium may be from about 0.4 atmto about 1.5 atm.

In carrying out the catalyst activation, nitrogen or anothersubstantially inert gas such as methane or carbon dioxide may bepresent, as may also other common components of crude acetylene, such asmethyl acetylene and ethylene. Oxygen, if present at all, issubstantially excluded from gas feeds during activation andethynylation, for safety reasons.

In small catalyst batches, the ethynylation catalyst may be slurried incold neutral formaldehyde solution and the acetylene introduced as theslurry is heated. Equivalent results are obtained by heating thecatalyst slurry with formaldehyde at a relatively low temperature, suchas 70° C., for a period of several hours before introducing acetylene.For larger batches, the ethynylation catalyst may be introducedincrementally to a hot, neutral formaldehyde solution under acetylenepressure. The aqueous solution may advantageously be a stream containingpropargyl alcohol and/or butynediol, e.g., a recycle stream.

The catalyst activation reaction is typically continued until the cupriccopper is substantially completely converted to cuprous copper form,which, with the cupric precursors, generally requires 4 to 48 hoursafter all the precursor has been contacted under the prescribedconditions. Additionally, the prescribed conditions of temperature, pHand acetylene/formaldehyde concentration balance and range will bemaintained throughout the catalyst activation. However, departures fromthe prescribed conditions during the course of the preparation reactioncan be tolerated, as the reaction is relatively insensitive to minorchanges in operating conditions.

The pH of the aqueous medium normally decreases as the reactionproceeds, at a rate and to an extent, which tends to increase with theinitial acidity of the reaction medium and also with the reactiontemperature. Accordingly, the pH may be controlled from 3 to 10, byoperating at a temperature from about 60° C. to about 120° C. Additionalcontrol may be achieved by adding small amounts of an acid acceptor tothe reaction. Illustrative acid acceptor may include, but are notlimited to, sodium acetate. Further control may be achieved by carryingout the catalyst generation as a continuous stirred reaction, freshneutral formaldehyde solution being continuously introduced into anagitated reaction zone, (any acidic effluent may, if desired, befiltered away from the copper-containing particles) as the reactionproceeds, all the while maintaining the acetylene partial pressure.

The ethynylation reaction comprises contacting an activated ethynylationcatalyst at a partial pressure of not more than about 1.9 atm with anaqueous slurry of the catalyst as above described, in a continuousstirred reaction at a temperature from about 80° C. to about 120° C. Theformaldehyde and acetylene may be continuously fed into the reactionzone where they are introduced into and below the surface of, theaqueous catalyst slurry, and thoroughly mixed into the same by vigorousagitation, and effluent is continuously withdrawn.

The reaction temperature for ethynylation is typically from about 60° C.to about 120° C., This may include a reaction temperature of about 80°C. to about 115° C., or from about 85° C. to about 110° C.Advantageously, the pH of the reaction mixture is from about 3 to about10. This may include a pH of about 4.5 to about 7. The pH may bemaintained by ion exchange or acid acceptor treatment of the continuousfeed or by addition of a suitable buffering agent.

The formaldehyde concentration in the liquid medium in contact with theslurried catalyst in the course of the ethynylation reaction may be fromabout 0.5 wt % to about 60 wt % under stead state conditions. This mayinclude a concentration from about 0.5 wt % to about 37 wt %. Theacetylene partial pressure may be at least 0.5 atm. Advantageously, theacetylene partial pressure may be from about 0.4 atm to about 1.9 atm.In some embodiments, the acetylene partial pressure above the aqueousmedium may be from about 0.5 atm to about 1.5 atm, and the catalyst willbe present from about 1 wt % to 20 wt %. The acetylene partial pressuremay be determined as the total pressure minus the absolute pressure ofwater and formaldehyde at the reaction temperature. As in the catalystgeneration, crude acetylene may be used, but for safety reasons itshould be advantageously substantially free of oxygen.

The effluent from the reaction zone may be heated and/or subjected toreduced pressure to volatilize formaldehyde, propargyl alcohol and aportion of the water which are condensed and combined with supplementalconcentrated formaldehyde for recycling to the ethynylation reactor,purging buildup of methanol at convenient intervals in a continuousoperation, and sending the balance of effluent as aqueous alkynoldirectly to hydrogenation. Alternatively, effluent from the reactionzone may be fed to a conventional plug flow ethynylation to react anyexcess formaldehyde.

In another aspect, a catalyst useful in hydrogenations is provided. Forexample, the catalyst may be used in the hydrogenation of butyraldehydeto n-butanol. The catalyst may be prepared by an impregnation processsimilar to that as described above. The impregnation technique includesthe addition of a multifunctional carboxylic acid to an impregnationsolution whereby the dispersion of the active metal is dramaticallyimproved. The catalyst is a copper oxide-based catalyst that is highlyactive in the hydrogenation of butyraldehyde to n-butanol.

In the impregnation process, the multifunctional carboxylic acid isadded to an aqueous solution of copper ions to prepare a dispersion thatis then applied to a metal oxide carrier to form an impregnated metaloxide carrier. The impregnated metal oxide carrier is then dried toremove free water, followed by heat-treating to prepare the catalyst.

The copper ions may be the result of the aqueous dissolution of a coppersalt in water. Illustrative copper salts are described above, andinclude, but are not limited to, copper sulfate and copper nitrate. Insome embodiments, the copper salt is Cu(NO₃)₂.

Illustrative multifunctional carboxylic acids are also described above,and include, but are not limited to glutaric acid, citric acid, andmalonic acid. In some embodiments, of the hydrogenation catalyst,glutaric acid is employed. When preparing the aqueous solution, themultifunctional carboxylic acid may be added to a nearly saturatedsolution of copper. For example, where the copper is present from thedissolution of copper nitrate, the saturated solution at roomtemperature is approximately 16 wt % in the water. A ratio of copperions to acid on a mol basis is from approximately 4 to 8. In someembodiments the ratio of copper ions to acid on a mol basis isapproximately 6. In some embodiments, ratio of copper ions to glutaricacid on a mol basis is from approximately 4 to 8. In some embodiments,ratio of copper ions to glutaric acid on a mol basis is approximately 6.It has been shown that the activity of the catalyst increasesproportionally to the copper surface area on the support. See Example 1.

In another aspect, a method is provided for preparing a hydrogenationcatalyst using pyrolysis conditions in comparison to the calcinationconditions described above. The difference being that under pyrolysisconditions, the heat-treatment of the dried impregnated carrier isconducted in an oxygen-limited atmosphere as compared to being done inair in the calcination process. As used herein, the term “oxygen-limitedatmosphere” refers to the heat treatment being done in an atmospherecontaining less than about 21 vol % of O₂. In some embodiments, thisincludes where the atmosphere contains less than about 5 vol % of O₂. Insome embodiments, this includes where the atmosphere is substantiallyoxygen-free (i.e. O₂-free). A substantially oxygen-free atmosphere isone in which steps are taken to remove and not introduce oxygen to theatmosphere and it may be conducted under an inert gas such as nitrogen,hydrogen, helium, neon, or argon.

It has been found that by performing the heat-treatment under pyrolysis(i.e. oxygen-limited) conditions, the Cu dispersion is substantiallyimproved on the metal oxide carrier, and lower amounts of themultifunctional carboxylic acid are requires. Without being bound bytheory, it is believed that the pyrolysis conditions lower the severityof exotherm experienced during calcination, the exotherm beingresponsible for sintering of the copper species. It was also observedthat performance and Cu dispersion go through a maximum, and thendecrease rapidly with increasing carboxylic acid addition. It wasobserved that this decrease in performance at higher acid additionamounts is due to the increased exotherm that occurs upon calcinationand decomposition (combustion) of the carboxylic acid.

The present invention, thus generally described, will be understood morereadily by reference to the following examples, which are provided byway of illustration and are not intended to be limiting of the presentinvention.

The present technology thus described, it will be more specificallydescribed and explained by means of the following examples, which arenot to be considered as limiting but merely illustrative of theinvention. All parts and proportions therein as well as in the appendedclaims are by weight unless otherwise specified.

EXAMPLES

Ethynylation Catalysis

Testing was carried out in two steps. First, the catalyst was activatedto form the active copper acetylide. Second, the activated catalyst wasthen transferred to the reaction vessel.

Catalyst Activation.

Catalyst activation was carried out in a 4-port quartz reactor flaskcontaining 100 ml formalin (37 wt % formaldehyde in water). The pH ofthe formalin was initially adjusted to about 8 by adding 1.5 M NaOH.Next, 15 g of catalyst were added to the pH adjusted formalin. The flaskwas purged with nitrogen, stirring was started, and acetylene wasintroduced at 50 m/min to the catalyst—formalin slurry at roomtemperature. The flask was then lowered into a recirculating water bathand heated to 80° C. This procedure forms the active Cu(I) acetylidespecies [Cu₂C₂].

The formic acid produced in this step was continuously neutralized byadding 1.5 M NaOH to the slurry, thus keeping the pH at about 8. After 5hours, the reactor was cooled to room temperature under flowingacetylene. Once it reached room temperature, acetylene was purged fromthe flask with nitrogen, the reactor was disassembled, and the slurryremoved. It was weighed, centrifuged, and decanted, leaving wet catalystready for activity testing.

Ethynylation Reaction.

Reaction studies were carried out using 0.5 g of the activated catalyst(dry basis) loaded into a stainless steel stirred autoclave containing45 ml formalin. As with the activation procedure, the pH of the formalinwas initially adjusted to about 8. The reactor was purged with nitrogenand acetylene before starting the reaction. The reactor was operated ina semi-batch fashion while stirring at 1450 RPM. At the start, acetylenefrom pressurized ballast cylinders was introduced to the reactor througha pressure regulator set at 15 psig (the reaction pressure), and thereactor was heated at approximately 2° per min to 80° C. After 5 hours,the reactor was cooled in flowing acetylene and subsequently purged withnitrogen. The slurry was removed, centrifuged, and decanted. The productmixture was analyzed by gas chromatography in which butynediol (primaryproduct) and propargyl alcohol (product intermediate) were quantified.Because formaldehyde is not readily detected by gas chromatographicanalysis, a sodium sulfite titration method was used to determine theamount of formaldehyde remaining in the product. Thus, overallformaldehyde conversion was calculated based on 300 min reaction timeand 0.5 g catalyst; and the initial catalytic reaction rate in terms ofkg formaldehyde converted per kg of catalyst per hour was calculated.

Activity Comparison.

Conditions are given in the “catalyst testing procedure” section. Theprocess/catalyst activity is measured by the rate of formation ofbutynediol as measured as the moles of butyndiol produced per minute pergram of catalyst [mol/min/g-cat].

Copper Dispersion.

The dispersion of Cu is calculated by dividing the moles of surfaceCu(0) atoms to the moles of total Cu(0) atoms on the catalyst. It ismeasured by a selective N₂O dissociation method that is standardpractice in the art (Chinchen et al. Journal of Catalysis 103(1): 79-86.(1987)). The procedure for determining Cu dispersion and Cu surface areais as follows: The calcined catalyst is reduced at 210° C. for 90minutes after a 5° C./min ramp in 5% H₂/95% N₂ gas. The reduced catalystis cooled to 60° C. and held at that temperature for 15 minutes while itis purged with He. At 60° C., 2% N₂O/98% He is passed over the reducedcatalyst and the evolution of N₂ is observed by a thermal conductivitydetector in conjunction with a liquid Ar cooled trap which condensesunreacted N₂O. The measurement is completed when no further N₂ isevolved. The amount of N₂O consumed and N₂ evolved to follow thereaction chemistry:N₂O+2Cu→N₂+Cu₂O,on the surface of the reduced catalyst and the reaction does not occurin the bulk (i.e. subsurface) Cu(0) layers. The Cu dispersion is thencalculated by taking the ratio of surface Cu(0) atoms per gram catalystmeasured by this method (i.e. atoms N₂ evolved multiplied by 2) dividedby the total number of Cu(0) atoms per gram catalyst.

Catalyst Activation.

In an inert atmosphere (nitrogen), heat the catalyst up in the reactorto 170 C and dwell until the temperature is stable. Introduce 5 vol % ofhydrogen gas and decrease the inert gas by 5 vol % to maintain aconstant gas volumetric flowrate and dwell for 1 hour. Increase thehydrogen concentration to 10 vol % and decrease the nitrogen another 5vol % to maintain a constant gas volumetric flowrate and dwell for 1hour. Increase the hydrogen concentration to 20 vol % and decrease thenitrogen another 10 vol % to maintain a constant gas volumetric flowrateand dwell for 1 hour. Increase the hydrogen concentration to 50 vol %and decrease the nitrogen another 30 vol % to maintain a constant gasvolumetric flowrate and dwell for 1 hour. Increase the hydrogenconcentration to 100 vol % such that the total volumetric flow ratedecreases to 80% of the original flow rate and dwell for 1 hour. Oncethis procedure is completed, the catalyst has been reduce whereby CuOhas been converted to Cu(0) and the catalyst is ready to be set toreaction conditions.

Reaction Conditions.

The butyraldehyde hydrogenation can be run as a vapor phase reaction oras a high-pressure trickle bed reaction. The gas phase reactionconditions are: 100° C., 2.1 barg, LHSV 3 hr⁻¹, and a ratio ofH₂:butyraldehyde of 30:1. The reaction data provided in entries 1-3 areunder these conditions. The reaction was monitored by a gaschromatograph with a flame ionization detector calibrated for theinvolved compounds. The catalysts prepared show nearly 100% selectivity.

Characterization of the Catalyst.

In order to note the coverage of Cu and Bi oxides around the support,Scanning Electron Microscopy (SEM) was used as seen in FIGS. 1-42. Thebrighter portions of the catalyst show the copper and bismuth oxides,whereas the darker gray portions indicate the support oxide.

Example 1

A series of four catalysts were synthesized by applying a solutioncontaining metal nitrates (14.0 wt % Cu, 2.6 wt % Bi) and 0-10 wt %citric acid (CA) to a silica support until reaching incipient wetnessimpregnation (filling 90% of the pore volume (measured by N₂ adsorption)of the support) while mixing the powder. The pore volume of the silicais 1.4 ml/g. The powder is then dried at 110° C. for at least 12 hours.The dried powder is then calcined in air at 500° C. for 2 hoursfollowing a 1° C./min ramp to the final temperature.

Samples Example-1A (0 wt % CA), (1 wt % CA), Example-1B (5 wt % CA), andExample-1C (10 wt % CA). The catalysts had the nominal composition of21.3 wt % CuO, 3.7 wt % Bi₂O₃, and 75 wt % SiO₂. FIG. 43 is a graphillustrating the improved activity of the catalyst observed in theethynylation reaction (combination of 2 moles of formaldehyde with 1mole of acetylene to form one mole of 1,4-butynediol) by addingincreasing amounts of citric acid to the impregnation (IWI) solution.The improvement to Cu dispersion can be observed qualitatively in thebackscatter SEM images with increasing citric acid content in theimpregnation solution FIGS. 1-6.

Example 2

A series of five catalyst are synthesized by applying a solutioncontaining metal nitrates (14.0 wt % Cu, 2.6 wt % Bi) and 0-10 wt %glutaric acid (GA) to a silica support until reaching incipient wetnessimpregnation (filling 90% of the pore volume (measured by N₂ adsorption)of the support) while mixing the powder. The pore volume of the silicais 1.4 ml/g. The powder is then dried at 110° C. for at least 12 hours.The dried powder is then calcined in air at 500° C. for 2 hoursfollowing a 1° C./min ramp to the final temperature.

Samples Example 2A (0 wt % GA), Example 2B (1 wt % GA), Example 2C (5 wt% GA), Example 2D (7 wt % GA), and Example 2E (10 wt % GA). Thecatalysts had the nominal composition of 21.3 wt % CuO, 3.7 wt % Bi₂O₃,and 75 wt % SiO₂. FIG. 44 illustrates the improved activity of thecatalyst observed in the ethynylation reaction (combination of 2 molesof formaldehyde with 1 mole of acetylene to form one mole of1,4-butynediol) by adding increasing amounts of glutaric acid to theimpregnation solution. An interesting feature of the plot is theexistence of a clear optimum in activity. The improvement to Cudispersion can be observed qualitatively in the backscatter SEM imageswith increasing glutaric acid content in the impregnation solution.(FIGS. 7-16)

Example 3

A series of five catalyst are synthesized by applying a solutioncontaining metal nitrates (15.3 wt % Cu, 1.0 wt % Bi) and 0-7.5 wt %malonic acid (MA) to a silica support until reaching incipient wetnessimpregnation (filling 90% of the pore volume (measured by N2 adsorption)of the support) while mixing the powder. The pore volume of the silicais 1.4 mL/g. The powder is then dried at 110° C. for at least 12 hours.The dried powder is then calcined in air at 500° C. for 2 hoursfollowing a 1° C./min ramp to the final temperature.

Samples Example 3A (0 wt % MA), Example 3B (2.5 wt % MA), Example 3C(4.2 wt % MA), Example 3D (5.8 wt % MA), and Example 3E (7.5 wt % MA).The catalysts had the nominal composition of 29.2 wt % CuO, 1.7 wt %Bi₂O₃, and 69.1 wt % SiO₂. FIG. 45 illustrates the improved activity ofthe catalyst observed in the ethynylation reaction (combination of 2moles of formaldehyde with 1 mole of acetylene to form one mole of1,4-butynediol) by adding increasing amounts of malonic acid to theimpregnation solution. The improvement to Cu dispersion can be observedquantitatively in FIG. 46 below and qualitatively in the backscatter SEMimages with increasing malonic acid content in the impregnation solution(FIGS. 17-26).

Example 4

A series of four catalyst are synthesized by applying a solutioncontaining metal nitrates (15.3 wt % Cu, 1.0 wt % Bi) and 0-7.5 wt %glutaric acid (GA) to a silica support until reaching incipient wetnessimpregnation (filling 90% of the pore volume (measured by N₂ adsorption)of the support) while mixing the powder. The pore volume of the silicais 1.7 ml/g. The powder is then dried at 110° C. for at least 12 hours.The dried powder is then calcined in air at 500° C. for 2 hoursfollowing a 1° C./min ramp to the final temperature.

Samples Example 4A (0 wt % GA), Example 4B (3.0 wt % GA), Example 4C(5.0 wt % GA), and Example 4D (7.0 wt % GA). The catalysts had thenominal composition of 29.1 wt % CuO, 1.7 wt % Bi₂O₃, and 69.2 wt %SiO₂. FIG. 47 illustrates the improved activity of the catalyst observedin the ethynylation reaction (combination of 2 moles of formaldehydewith 1 mole of acetylene to form one mole of 1,4-butynediol) by addingincreasing amounts of glutaric acid to the impregnation solution. Theimprovement to Cu dispersion can be observed quantitatively in FIG. 48,may also be observed in the backscatter SEM images with increasingglutaric acid content in the impregnation solution. There is a clearcorrelation between the Cu dispersion and the catalyst activity (FIGS.27-32).

Example 5

A series of five catalysts were synthesized by applying a solutioncontaining metal nitrates (7.7 wt % Cu, 0.5 wt % Bi) and 1.5-7.0 wt %glutaric acid (GA) to a silica support until reaching incipient wetnessimpregnation (filling 90% of the pore volume (measured by N₂ adsorption)of the support) while mixing the powder. The pore volume of the silicais 1.7 ml/g. The powder is then dried at 110° C. for at least 12 hours.The dried powder is then calcined in air at 500° C. for 2 hoursfollowing a 2° C./min ramp to the final temperature.

Samples Example 5A (1.5 wt % GA), Example 5B (2.5 wt % GA), Example 5C(3.5 wt % GA), Example 5D (5.0 wt % GA), Example 5E (7.0 wt % GA). Thecatalysts had the nominal composition of 15.1 wt % CuO, 0.9 wt % Bi₂O₃,and 84.0 wt % SiO₂. FIG. 49 illustrates the improved activity of thecatalyst observed in the ethynylation reaction (combination of 2 molesof formaldehyde with 1 mole of acetylene to form one mole of1,4-butynediol) by adding increasing amounts of glutaric acid to theimpregnation solution. This plot shows that the metal:acid ratio, ofabout 6 is optimum for glutaric acid and Cu/Bi nitrates. The improvementto Cu dispersion can be observed qualitatively in the backscatter SEMimages with increasing glutaric acid content in the impregnationsolution. (FIGS. 33-42).

Example 6

A series of five catalysts were synthesized by applying a solutioncontaining metal nitrates (15.3 wt % Cu, 1.0 wt % Bi) and 5.0 wt %glutaric acid to a silica support until reaching incipient wetnessimpregnation (filling 90% of the pore volume (measured by N₂ adsorption)of the support) while mixing the powder. The pore volume of the silicais 1.7 ml/g. The powder is then dried at 110° C. for at least 12 hours.The dried powder is then calcined in air at 250-500° C. for 2 hoursfollowing a 2° C./min ramp to the final temperature.

Samples Example 6A (250° C.), Example 6B (300° C.), Example 6C (350°C.), Example 6D (400° C.), and Example 6E (500° C.). The catalysts hadthe nominal composition of 33.4 wt % CuO, 1.9 wt % Bi₂O₃, and 64.7 wt %SiO₂. FIG. 50 illustrates the improved activity of the catalysts ofExamples 6A-E observed in the ethynylation reaction (combination of 2moles of formaldehyde with 1 mole of acetylene to form one mole of1,4-butynediol) by varying the calcination temperature between 250-500°C.; 350° C. being the optimal value to fully decompose any metal saltsor organic acid on the catalyst. The improvement to Cu dispersion forExamples 6A, 6C and 6E can be observed quantitatively in FIG. 51 whichcorrelates with the activity of the catalyst.

Hydrogenation Catalysis

Methodology.

Cu dispersions are measured by a selective N₂O dissociation method thatis standard practice in the art (Chinchen, G. C., et al. Journal ofCatalysis 103(1): 79-86 (1987). The procedure for determining Cudispersion and Cu surface area is as follows. The calcined catalyst isreduced at 210° C. for 90 minutes after a 5° C./min ramp in 5% H₂/95% N₂gas. The reduced catalyst is cooled to 60° C., and held at thattemperature for 15 minutes while it is purged with He. At 60° C., 2%N₂O/98%, and He is passed over the reduced catalyst and the evolution ofN₂ is observed by a thermal conductivity detector in conjunction with aliquid Ar cooled trap which condenses unreacted N₂O. The measurement iscompleted when no further N₂ is evolved. The amount of N₂O consumed, andN₂ evolved, is assumed to follow the reaction chemistry N₂O+2Cu→N₂+Cu₂Oon the surface of the reduced catalyst and the reaction does not occurin the bulk (i.e. subsurface) Cu layers. The Cu dispersion is thencalculated by taking the ratio of surface Cu atoms per gram catalystmeasured by this method (i.e. atoms N₂ evolved multiplied by 2) dividedby the total number of Cu atoms per gram catalyst.

Example 7

Three catalysts were synthesized by applying a solution containingcopper nitrate (16.0 wt % Cu) and 0 or 5 wt % glutaric acid (GA), to asilica support until reaching incipient wetness impregnation (filling90% of the pore volume of the support, as measured by N₂ adsorption)while mixing the powder. The pore volume of the silica was 1.7 mL/g. Thepowder was then dried at 110° C. for at least 12 hours. The dried powderwas then heated at a 1° C./min ramp to a final temperature of 350° C. or500° C., where it was calcined in air for 2 hours.

Table 1 below gives the activity data for the hydrogenation ofbutyraldehyde to butanol, the copper dispersion of the said catalysts,the amount of glutaric acid used in modifying the incipient wetnessimpregnation (IWI) solution, the corresponding loading, and thecalcination temperature. Entry 2 demonstrates the improvement toactivity and dispersion over Entry 1, when modifying the IWI solutionwith glutaric acid. Entry 3 demonstrates that calcination optimizationcould further enhance activity and copper dispersion. It has been foundthat the catalyst activity appears to be directly proportional to thecopper surface area of the catalyst. For example, increasing the Cu(0)can increase the activity of the catalyst to a similar degree.

TABLE 1 Cu(0) Cu(0) GA Calc. Disp. Surface Entry (wt %) Cu (wt %) Temp.(° C.) Activity^(a) (mol %) Area^(b) 1 0.0 20.0 500 0.05 0.01 0.01 2 5.030.4 500 5.28 1.07 2.29 3 5.0 26.6 350 16.14 2.97 5.49 ^(a)Units are molbutyraldehyde reacted/kg-cat/hour ^(b)Units are m²Cu(0)/g catalyst.

Example 8

It was demonstrated that acids other than glutaric, such as citric acid,can likewise improve the copper dispersion by modifying the IWI solutionused in the synthesis. Four catalysts were synthesized by applying asolution containing copper nitrate (16.0 wt % Cu) and 0, 3, 5, or 7 wt %citric acid (CA) to a silica support until reaching incipient wetnessimpregnation (filling 90% of the pore volume of the support, as measuredby N₂ adsorption) while mixing the powder. The pore volume of the silicawas 1.7 mL/g. The powder was then dried at 110° C. for at least 12hours. The dried powder was then heated at a 1° C./min ramp to a finaltemperature of 500° C., where the dried powder was calcined in air at500° C. for 2 hours. Table 2 illustrates the improvement to Cudispersion with the addition of citric acid into the impregnationsolution.

TABLE 2 CA Cu Calc. Cu(0) Disp. Cu(0) Surface Entry (wt %) (wt %) Temp.(mol %) Area^(b) 1 0.0 20.0 500 0.01 0.01 4 3.0 18.4 500 0.02 0.03 5 5.020.2 500 0.15 0.20 6 7.0 25.8 500 2.12 3.53

Example 9

The following examples demonstrate how different shapes and dimensionsof silica supports still exhibit a significant improvement to Cudispersion by adding glutaric acid (GA) at 5 wt % (Cu:GA˜6). Thecatalysts were synthesized by applying a solution containing coppernitrate (16.0 wt % Cu) and 0-7 wt % glutaric acid to a silica supportuntil reaching incipient wetness impregnation (filling 90% of the porevolume of the support, as measured by N₂ adsorption) while mixing thematerial. Different support shapes were utilized including powders,spheres, and extrudates. The pore volume of the powder was 1.7 mL/g,sphere 0.9 mL/g, and extrudate 0.7 mL/g. The resultant materials werethen dried at 110° C. for at least 12 hours. The dried powder was thencalcined in air at 500° C. for 2 hours, following a 1° C./min ramp tothe final temperature. The dried spheres and extrudates were thencalcined in air at 350° C. for 3 hours, following a/min ramp to thefinal temperature. Table 3 illustrates that the organic assistedimpregnation is effective with support powders or shaped supports.

TABLE 3 Calc. Cu(0) Cu(0) GA Cu Temp. Disp. Surf. Avg. Entry (wt %) (wt%) (° C.) (mol %) Area^(b) Shape Size 1 0.0 20.0 500 0.01 0.01 Powder 45μm   2 5.0 30.4 500 1.07 2.29 Powder 45 μm   7 0.0 12.9 350 4.36 3.62Sphere 4 mm 8 1.0 13.7 350 2.50 2.20 Sphere 4 mm 9 2.0 14.5 350 2.142.00 Sphere 4 mm 10 3.0 15.0 350 2.34 2.27 Sphere 4 mm 11 4.0 17.1 3506.18 6.81 Sphere 4 mm 12 5.0 17.4 350 9.36 10.50 Sphere 4 mm 13 6.0 16.5350 5.26 5.59 Sphere 4 mm 14 0.0 11.1 350 0.50 0.33 Extrudate 2 mm 153.0 13.9 350 4.10 3.67 Extrudate 2 mm 16 5.0 14.8 350 4.90 4.62Extrudate 2 mm 17 7.0 14.5 350 3.80 3.52 Extrudate 2 mm

Example 10

The following entries demonstrated that a significant improvement to Cudispersion could be achieved irrespective of catalyst support. Severalcatalysts were synthesized by applying a solution containing coppernitrate (16.0 wt % Cu) and 0-7 wt % glutaric acid to a gamma aluminauntil reaching incipient wetness impregnation (filling 90% of the porevolume of the support, as measured by N₂ adsorption) while mixing thematerial. The pore volume of the alumina powder was 0.6 mL/g. Theresultant material was then dried at 110° C. for at least 12 hours. Thedried powder was then calcined in air at 500° C. for 2 hours, followinga 1° C./min ramp to the final temperature. Table 4 illustrates thecopper dispersion as a function of amount of glutaric acid on alumina.

TABLE 4 GA Cu Calc. Cu(0) Disp. Cu(0) Surface Entry (wt %) (wt %) Temp.(mol %) Area^(b) 18 0.0 8.0 500 1.38 0.71 19 3.0 9.8 500 3.88 2.45 205.0 9.6 500 5.75 3.56 21 7.0 9.2 500 5.91 3.50

Example 11

This example demonstrates that changing the calcination atmosphere fromair to nitrogen results in a substantial increase of Cu dispersion.These catalysts were synthesized by applying a solution containingcopper nitrate (16.0 wt % Cu) and 0-5 wt % glutaric acid to a silicasphere support (4 mm) until reaching incipient wetness impregnation(filling 90% of the pore volume of the support, as measured by N₂adsorption) while mixing the material. The pore volume of the silica was0.9 mL/g. The material was then dried at 110° C. for at least 12 hours.The dried powder was then calcined in the specified atmosphere at 350°C. for 3 hours following a/min ramp to the final temperature. Table 5illustrates the effects of pyrolysis v. air calcination on copperdispersion as a function of glutaric acid amount.

TABLE 5 GA Cu Cu(0) Disp. Cu(0) Surface Entry (wt %) (wt %) Atmosphere(mol %) Area^(b) 22 0.0 12.1 Air 1.12 0.87 23 3.0 14.8 Air 2.77 2.64 244.0 14.5 Air 4.63 4.32 25 5.0 14.5 Air 7.44 6.95 26 0.0 12.8 Nitrogen2.66 2.19 27 3.0 15.5 Nitrogen 7.24 7.23 28 3.5 15.6 Nitrogen 9.95 10.0029 4.0 15.4 Nitrogen 9.23 9.16

Example 12

Copper dispersions are prepared by pyrolyzing in a nitrogen atmosphereby which the decomposition (i.e. combustion) of the glutaric acidbecomes less exothermic in nature. This occurs because NO₂ as anoxidizing agent as observed by more NO formation during the calcinationin nitrogen than in the calcination with air. The following dataillustrates that a weaker exotherm is exhibited by the sample whencalcined in nitrogen, when compared to air. The lesser exotherm causesthe catalyst to experience a lower overall temperature and undergo lesssintering during calcination which in turn leads to higher Cu(0) surfacearea and catalyst activity. Table 6 illustrates the effects of pyrolysisv. air calcination on the exothermicity of the calcination process.

TABLE 6 Entry GA (wt %) Atmosphere Heat Released 30 3.5 Air −163.9 J/g31 3.5 Nitrogen −126.8 J/g 32 5.0 Air −232.8 J/g 33 5.0 Nitrogen −159.0J/g

Thermal gravimetric analysis (TGA), differential scanning calorimetry(DSC), and mass spectrometer (MS) were carried out according to thefollowing methodology. About 85 mg of sample was under 100 mL/min of theselected atmosphere gas. The sample was ramped from room temperature to120° C. at 5° C./min, and held at that temperature for 10 minutes. Thesample was then ramped to 400° C. at 5° C./min. The change in sampleweight was monitored by thermal gravimetric analysis and the heatevolution by differential scanning calorimetry.

While certain embodiments have been illustrated and described, it shouldbe understood that changes and modifications can be made therein inaccordance with ordinary skill in the art without departing from thetechnology in its broader aspects as defined in the following claims.

The embodiments, illustratively described herein may suitably bepracticed in the absence of any element or elements, limitation orlimitations, not specifically disclosed herein. Thus, for example, theterms “comprising,” “including,” “containing,” etc. shall be readexpansively and without limitation. Additionally, the terms andexpressions employed herein have been used as terms of description andnot of limitation, and there is no intention in the use of such termsand expressions of excluding any equivalents of the features shown anddescribed or portions thereof, but it is recognized that variousmodifications are possible within the scope of the claimed technology.Additionally, the phrase “consisting essentially of” will be understoodto include those elements specifically recited and those additionalelements that do not materially affect the basic and novelcharacteristics of the claimed technology. The phrase “consisting of”excludes any element not specified.

The present disclosure is not to be limited in terms of the particularembodiments described in this application. Many modifications andvariations can be made without departing from its spirit and scope, aswill be apparent to those skilled in the art. Functionally equivalentmethods and compositions within the scope of the disclosure, in additionto those enumerated herein, will be apparent to those skilled in the artfrom the foregoing descriptions. Such modifications and variations areintended to fall within the scope of the appended claims. The presentdisclosure is to be limited only by the terms of the appended claims,along with the full scope of equivalents to which such claims areentitled. It is to be understood that this disclosure is not limited toparticular methods, reagents, compounds compositions or biologicalsystems, which can of course vary. It is also to be understood that theterminology used herein is for the purpose of describing particularembodiments only, and is not intended to be limiting.

In addition, where features or aspects of the disclosure are describedin terms of Markush groups, those skilled in the art will recognize thatthe disclosure is also thereby described in terms of any individualmember or subgroup of members of the Markush group.

As will be understood by one skilled in the art, for any and allpurposes, particularly in terms of providing a written description, allranges disclosed herein also encompass any and all possible subrangesand combinations of subranges thereof. Any listed range can be easilyrecognized as sufficiently describing and enabling the same range beingbroken down into at least equal halves, thirds, quarters, fifths,tenths, etc. As a non-limiting example, each range discussed herein canbe readily broken down into a lower third, middle third and upper third,etc. As will also be understood by one skilled in the art all languagesuch as “up to,” “at least,” “greater than,” “less than,” and the like,include the number recited and refer to ranges which can be subsequentlybroken down into subranges as discussed above. Finally, as will beunderstood by one skilled in the art, a range includes each individualmember.

All publications, patent applications, issued patents, and otherdocuments referred to in this specification are herein incorporated byreference as if each individual publication, patent application, issuedpatent, or other document was specifically and individually indicated tobe incorporated by reference in its entirety. Definitions that arecontained in text incorporated by reference are excluded to the extentthat they contradict definitions in this disclosure.

Other embodiments are set forth in the following claims.

What is claimed is:
 1. A catalyst precursor composition comprising: ametal oxide carrier impregnated with an aqueous solution, the aqueoussolution consisting essentially of water, a copper salt, optionally abismuth salt, optionally a precipitation agent and from about 1 wt % toabout 15 wt % of a C₃-C₆ multifunctional carboxylic acid.
 2. Thecatalyst precursor composition of claim 1, wherein the copper saltcomprises copper nitrate, copper sulfate, copper acetate, copperchloride, or copper citrate.
 3. The catalyst precursor composition ofclaim 1, wherein the bismuth salt is present.
 4. The catalyst precursorcomposition of claim 3, wherein the bismuth salt comprises bismuthnitrate, bismuth sulfate, bismuth acetate, bismuth chloride, or bismuthcitrate.
 5. The catalyst precursor composition of claim 1, wherein themultifunctional carboxylic acid is a C₃-C₅ multi-carboxylic acid.
 6. Thecatalyst precursor composition of claim 1, wherein the aqueous solutioncomprises from about 2.5 wt % to about 7 wt % of the C₃-C₆multifunctional carboxylic acid.
 7. The catalyst precursor compositionof claim 1, wherein the metal oxide carrier is a siliceous oxidecomprising silica or silica and gamma-alumina.
 8. The catalyst precursorcomposition of claim 1, wherein upon drying of the aqueous solution toform a dried, impregnated carrier, and heat-treating of the dried,impregnated carrier, a catalyst is formed consisting of about 5 wt % toabout 50 wt % copper oxide and optionally bismuth oxide.
 9. The catalystprecursor composition of claim 8, wherein the drying is carried out at atemperature from about 100° C. to about 125° C. for a period of timesufficient to remove substantially all water.
 10. The catalyst precursorcomposition of claim 8, wherein the heat-treating comprises calcining inair.
 11. The catalyst precursor composition of claim 8, wherein theheat-treating comprises pyrolyzing in an atmosphere substantially freeof oxygen at a temperature from about 250° C. to about 750° C.
 12. Thecatalyst precursor composition of claim 8, wherein the heat-treatingcomprises calcination in an oxygen-limited atmosphere has less than 21vol % oxygen.
 13. The catalyst precursor composition of claim 7, whereinthe catalyst is a hydrogenation catalyst, a dehydrogenation catalyst, ora hydrogenolysis catalyst.
 14. A catalyst for hydrogenation,dehydrogenation, hydrogenolysis, or ethynylation, the catalystconsisting essentially of from about 5 wt % to about 50 wt % copperoxide and optionally bismuth oxide, and wherein the catalyst is preparedby a process comprising: impregnating a metal oxide carrier with anaqueous solution to form an impregnated carrier; drying the impregnatedcarrier to form a dried, impregnated carrier; and heat-treating thedried, impregnated carrier in air to form the catalyst; wherein: theaqueous solution consists essentially of water, a copper salt,optionally a bismuth salt, and optionally a precipitation agent; andfrom about 1 wt % to about 15 wt % of a C₃-C₆ multifunctional carboxylicacid.
 15. The catalyst of claim 14, wherein the copper salt comprisescopper nitrate, copper sulfate, copper acetate, copper chloride, orcopper citrate.
 16. The catalyst of claim 14, wherein the catalyst is anethynylation catalyst and the bismuth salt is present and the catalystcontains up to about 5 wt % Bi₂O₃.
 17. The catalyst of claim 16, whereinthe bismuth salt comprises bismuth nitrate, bismuth sulfate, bismuthacetate, bismuth chloride, or bismuth citrate.
 18. The catalyst of claim14, wherein the multifunctional carboxylic acid is a C₃-C₅multi-carboxylic acid.
 19. The catalyst precursor composition of claim1, wherein the aqueous solution consists of water, a copper salt,optionally a bismuth salt, optionally a precipitation agent and fromabout 1 wt % to about 15 wt % of a C₃-C₆ multifunctional carboxylicacid.
 20. The catalyst of claim 14, wherein the aqueous solutionconsists of water, a copper salt, optionally a bismuth salt, optionallya precipitation agent and from about 1 wt % to about 15 wt % of a C₃-C₆multifunctional carboxylic acid.